Prime Minister Stephen Harper’s office says he chose not to speak to the chief justice of the Supreme Court of Canada about a planned appointment to the court after he was advised such a conversation would be “inadvisable and inappropriate.”

On Thursday, Harper’s office reacted to media reports about how a staff member for Chief Justice Beverley McLachlin had attempted to douse rumours that she allegedly lobbied against the appointment of Marc Nadon to the court — an appointment later overturned by the court itself as unconstitutional.

Frustrations inside the Harper government at the recent string of losses at the Supreme Court are in danger of boiling over.

One minister said he had been advised not to get into a public “firefight,” but senior Conservatives are privately incensed and feel the court has blocked Parliament’s ability to make laws.

Rumours about Beverley McLachlin, the Chief Justice, are being shared with journalists, alleging she lobbied against the appointment of Marc Nadon to the court (an appointment later overturned as unconstitutional). It is also being suggested she has told people the Harper government has caused more damage to the court as an institution than any government in Canadian history.

“Neither the Prime Minister nor the Minister of Justice would ever call a sitting judge on a matter that is or may be before their court,” said the statement issued by Harper’s office.

“The Chief Justice initiated the call to the Minister of Justice. After the Minister received her call he advised the Prime Minister that given the subject she wished to raise, taking a phone call from the Chief Justice would be inadvisable and inappropriate. The Prime Minister agreed and did not take her call.”

The PMO statement came in the wake of a media report about the matter.

McLachlin’s executive legal officer, Owen Rees, reportedly told the National Post in a statement that she did not lobby against the appointment but was consulted by a parliamentary committee on the government’s short list and the needs of the court.

“The question concerning the eligibility of a federal court judge for appointment to the Supreme Court under the Supreme Court Act was well-known in legal circles,” said Rees.

“Because of the institutional impact on the Court, the Chief Justice advised the Minister of Justice, Mr. [Peter] MacKay, of the potential issue before the government named its candidate for appointment to the Court. Her office also advised the Prime Minister’s chief of staff, Mr. [Ray] Novak. The Chief Justice does not express any views on the merits of the issue.”

Neither did she make disparaging remarks about the Conservative government, reported the Post. “She has stated publicly on several occasions that mutual respect between the branches of government — and their respective roles — is essential in a constitutional democracy,” said Rees.

In March, the top court rejected Nadon as Harper’s pick to be a Supreme Court justice — something he first announced last fall.

In the wake of an unprecedented ruling, the government appeared flat-footed, saying it was “surprised” by the development and was examining its “options.” Several weeks later, the government still has not announced its plans and the court is short one judge.

The landmark judgment by the high court nullified the government’s appointment last October of Nadon, a Federal Court of Appeals judge, on the grounds that he didn’t meet the eligibility criteria laid out in the Supreme Court Act.

The court also rejected as unconstitutional the government’s attempt to bypass those rules by retroactively amending the law. The Conservatives tried to redefine the law to support Nadon’s appointment, but only after it became clear his ascendance to the Supreme Court bench faced legal and political challenges.

Opposition parties blasted the government for bungling the appointment and urged Harper to quickly address Quebec’s reduced voice on the court. One of the province’s three seats on the court, which are guaranteed by the Constitution, has remained empty since last summer.

The 6-1 decision was a stunning political defeat for the Conservative government, the latest in a string of constitutional decisions from the top court that have not gone the government’s way. They include rulings over supervised injection sites, the country’s prostitution laws and a decision that struck down a Conservative government law on day parole.

On Thursday, the Prime Minister’s Office said the Department of Justice had sought outside legal advice from a former Supreme Court justice on eligibility requirements of federal court judges for the Supreme Court of Canada.

“This legal advice was reviewed and supported by another former Supreme Court justice as well as a leading constitutional scholar, and was made public. None of these legal experts saw any merit in the position eventually taken by the Court.”